Striking tool

ABSTRACT

A striking tool for crushing stonelike material, the tool having a double layer, one layer forming the working side and being prone to wear and the other layer forming the rear side being of a material having resistance to bending.

[451 Dec. 30, 1975 STRIKING TOOL 75] Inventor:

Wage'neder.........................

Hans Stiieber, Sonthofen, Germany Hans Smeber somhofen Germany PrimaryExaminer-Granville Y. Custer, Jr.

Attorney, Agent, or FirmSilverman & Cass, Ltd

4 7 9 1 5 n n. A e n: .w d Se SH... AF NH 72 Appl. No: 458,311

ABSTRACT [30] Foreign Application Priority Data Apr. 7 1973Germany............................ 2317692 A striking tool for crushingstonelike material, the tool having a double layer, one layer formingthe working side and being prone to wear and the other layer forming therear side being of a material having resistance to bending.

780 on UB 4 5 7 -0 7 u 7 mp MMS mn9 l "n ..1 WW "n W h c um l hcm 1 d LdUMF HUM 555 [56] References Cited UNITED STATES PATENTS 1,630,021 5/1927241/197 3 Claims, 2 Drawing Figures US. Patent Dec. 30, 1975 3,929,296

STRIKING TOOL BACKGROUND OF THE INVENTION 1. Field of the invention Thisinvention relates generally to striking tools, and more particularly, toan impact-hammer crusher arranged on a rotor positioned on horizontallyor vertically disposed bearings for crushing stonelike materials havinga working side limited in its upper area by a striking edge.

2. Description of the Prior Art Striking tools of the type with whichthis invention is concerned are known generally in the art. The mode ofoperation of the prior art provides for the striking tools rotating withhigh peripheral velocity-crush stones coming in the circle described bythe outermost edge of the striking tool principally through shearing-andthrow the pieces against stationary breaking elements.

The special feature of this crushing involves the fact that, with newlyinstalled striking tools, a generally desirable high proportion offinely-grained components is produced, whereby in addition the crushedindividual grain exhibits a compact form. These positive properties,however, are lost, in the case of the hitherto customary striking tools,with increasing wearing-out of the striking tool, in a constantlyincreasing degree, and the quality of the crushed materialcorrespondingly constantly decreases. Thus, through the wear of thestriking tools, the crushed material is qualitatively reduced. In thisconnection, in the wearing out of striking tools, one should basicallydifferentiate between strik ing wear and friction wear.

Striking wear occurs predominantly, directly at the front edge of thebreaking tool, the striking edge. Pure striking wear exists however onlyin the case of new tools, and is, thus, limited in time. In a newstriking tool, the striking edge is situated on the largest radius withregard to the rotor axis, i.e., the striking edge alone determines thestriking circle diameter. Thus, a new striking tool shows only strikingwear. Such striking wear is, however, limited to a short period, as withprogressing wear of the striking edge, friction wear occurs on theoutside of the tool in addition to striking wear.

During this short period, the quality of the breaking material isoptimal, since the energy residing in the rotor, is fully available forshearing an individual stone, and for hurling away the part of a stonewhich has penetrated into the striking circle.

Striking wear has the effect of rounding the striking edge, wherebyadditionally, friction wear occurs in the zone lying behind the strikingedge, the so-called outer surface. This friction wear uses up in anincreasing manner the outer surface and deforms the tool so as to risesteeply toward the rear, opposite the direction of rotation. Thisdeformation of the tool so as to rise steeply toward the rear, whichresults in the creation of an oblique outer surface, prevents apredominant portion of the stones falling through a chute from reachingthe actual striking edge as a result of the greater peripheral velocityof the striking tool vis a vis the velocity of the falling stones.

The pure shearing and striking effect is thus lost since the stonesslide on the oblique outer surface of the worn tool whereby the stone isnot acted upon by the striking edge. The stones thereby lose energy as aconsequence of frictional engagement with the oblique 2 surface arethrown off with a lesser tangential velocity as compared with thevelocity of the rotor. Hence, there no longer occurs a pronouncedshearing and striking effect. This results in, a significant reductionin quality, with regard to fineness of the crushed material, and theform of the individual particle.

The present invention has the object of constructing a striking tool ofthe type previously mentioned, in such a fashion that the reduction inquality of the breaking material with increasing wearing out of thestriking tool is largely avoided.

This problem is solved according to the invention in that the strikingtool is designed to have a double layer, in which one layer isconstructed as a working side, comprising a material prone to wear andthe other layer as a rear side ofa material having resistance tobending. This gives the advantage that the working side, in spite ofincreasing wear, preserves a sharp striking edge and remainscontinuously capable of functioning. On the other hand, the unavoidablefriction wear deforms the outer surface whereby the outer surface barelyprojects beyond the circle described by the striking edge.

In a further embodiment of the invention, the materials of both layerscan be formed as a composite material.

Furthermore, the striking edge, with continuous wearing out of thestriking tool, can exhibit a somewhat equal distance from the line ofseparation, between the two layers, whereby, in a simple manner, thepreservation of a sharp striking edge is assured.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 shows a lateral view of astriking tool according to the invention, with rotor in cross section;

FIG. 2 shows another embodiment of a striking tool with rotor.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The striking tool representedin Flg. 1 is arranged in a rotor 3, wherein the rotor 3 is moved in thedirection of arrow I.

The striking tool 1 has a working side 4, and a rear side 12. Theworking side 4 is bounded at the upper zone by a striking edge 2.

The striking tool 1 comprises the two layers 8 and 9, in which the layer8 constitutes the working side 4, while the layer 9 represents the rearside 12.

The layer 8 of the working side 4 comprises a material highly capable ofresistance to wear, but of low resistance to bending, while the layer 9comprises a material which has a high resistance to bending, but lowresistance to wear. By way of example, layer 8 could be composed ofchilled cast iron such as a cast steel of 3% C and l5-20% Cr.; layer 9could be composed of tough weldable steel or cast steel. The two layerscould be secured together as a lamination, by casting for example. Othercompositions or means of securement of the two layers are possible.

The front layer 8 comprising wear-resistant material, which constitutesthe working side 4, is embedded in the layer 9 of the rear side 12. Thecontour of the working side exhibits no deviation as compared with thecontour of conventional striking tools.

The contour of the border surface or interface 10 between the wearresistant but low bending resistant material of the layer 8, and thebending resistant but low wear resistant material of the layer 9 ischosen such 3 that with increasing wearing out W W of the wear resistantlayer, a comparatively sharp edge 11 remains, as the striking tool isworn back from the striking circle S to the striking circle S.

The layer 9 is, on the other hand, so worn out through friction wear,that its outer surface W2, W3, etc. does not project, or only slightlyprojects, over the circle described through the striking edge 11.

The thickness a of the wear resistant layer 8, some what increasesinwardly, such that the distance b of the striking edge 11 remainssubstantially proportional to the layer 9. The distance of the strikingedge 11 from the interface thus remains generally constant as measuredalong the Striking circle.

The rear side 12 of the striking tool 1 is contoured such that the layer9 exhibits consistent rigidity with respect to the striking and bendingload, but presents a minimum of an oblique outward friction surface soas to minimize frictional drag between the tool and stones to becrushed.

In the lower zone 7 of the striking tool 1, the layer 9 completelysurrounds the front layer 8 of the working side 4.

In FIG. 2, another embodiment 13 of a striking tool is represented,which is constructed as a striking hammer pivotally suspended in therotor 3, through a hinge 20. This striking tool or the striking hammer13 moves together with the rotor in the direction of arrow I. Thestriking tool is likewise made of composite material having a frontlayer 14, being wear resistant, which forms the working side 4 with thestriking edge 2. This wear resistant layer 14 is embedded in asupporting layer 15, of low wear resistance, but of high resistance tobending, which layer constitutes the rear side 12 of the striking tool.Again, through this combination is assured that also with increasingwearing out of the working side, a sharp striking edge is constantlypresent.

Both striking tools represented in the embodiments explained in theforegoing, are constructed in such a fashion that the working side 4 andthe rear side 12, define a body having a small striking surface, andequal resistance to bending at every point of the cross section, and atevery stage of wear. Through this, a fingerlike cross section ensues,which assures that a striking tool functioning efficiently is presenteven with increasing wear.

What is to be secured by Letters Patent of the United States is:

l. A striking tool for an impact and hammer crusher, the tool adapted tobe mounted on a rotor supported in a bearing and operable to rotate thetool at high velocity into engagement with stones along a strikingcircle for crushing same, the tool comprising an impact head formed of acomposite material comprising at least a pair of layers of materialhaving an intimately bonded interface, one layer providing a workingside of wearresistant material having a striking edge, the other layerformed of a material resistant to bending and having a low wearresistance, and wherein the upper surface of said other layersubstantially recedes relative to the striking edge of the working sideat an acute angle relative to a plane tangential to the striking edgeand generally normal to the striking circle.

2. The tool as claimed in claim 1 in which the working side and saidother side define a body wherein resistance to bending in every point ofits cross section remains generally constant in every stage of wear.

3. The tool as claimed in claim 1 in which the thickness of thewear-resistant material providing the striking edge remains a generallyequal distance from the interface between the two layers, as determinedby planes generally normally intersecting the striking circle, withprogressive wear of the striking tool.

UNITED STATES PATENT AND TRADEMARK OFFICE QQATE 0F CORRECTION PATENT NO.I 3,929,296

DATED 1 December 30, 1975 INVENTOR(S) I HANS STOEBER It is certifiedthat error appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

On the title page, block [75], change the inventor's name from "StSeber"to --Stoeberand in block [73], change the Assignee from "Hans Stbeber,Sonthofen" to -BHS-Bayerische Berg-, Hfittenund SalzwerkeAktiengesellschaft, Munich,.

Signed and Scaled this fourth Day of May 1976 [semi Atfesl.

RUTH C. MASON C. MARSHALL DANN Arresting Officer (umnrissimu'r oflulmrsand Trademarks

1. A striking tool for an impact and hammer crusher, the tool adapted to be mounted on a rotor supported in a bearing and operable to rotate the tool at high velocity into engagement with stones along a striking circle for crushing same, the tool comprising an impact head formed of a composite material comprising at least a pair of layers of material having an intimately bonded interface, one layer providing a working side of wear-resistant material having a striking edge, the other layer formed of a material resistant to bending and having a low wear resistance, and wherein the upper surface of said other layer substantially recedes relative to the striking edge of the working side at an acute angle relative to a plane tangential to the striking edge and generally normal to the striking circle.
 2. The tool as claimed in claim 1 in which the working side and said other side define a body wherein resistance to bending in every point of its cross section remains generally constant in every stage of wear.
 3. The tool as claimed in claim 1 in which the thickness of the wear-resistant material providing the striking edge remains a generally equal distance from the interface between the two layers, as determined by planes generally normally intersecting the striking circle, with progressive wear of the striking tool. 